Development and evaluation of a score to predict difficult epidural placement during labor.

International audienceBACKGROUND AND OBJECTIVES: Difficult epidural placement (DEP) during labor may be distressing for the patient and may increase the risk of dural puncture. A score predicting DEP based on the combination of individual risk factors could identify high-risk patients. This study aimed to identify risk factors for DEP and build a prediction score. METHODS: Three hundred thirty patients were prospectively included. Difficult epidural placement was defined as more than 1 skin puncture with a Tuohy needle. Dura puncture occurrence was recorded. The population was randomly split into a training set and a validation set. In the training set, risk factors were identified with logistic regression and used to build a score defining 3 risk groups. Model and score discrimination was assessed with the C-index and clinical usefulness of the score with decision curves. RESULTS: Difficult epidural placement frequency was 30% (95% confidence interval [95% CI], 25%-35%). Dural puncture was more frequent in DEP patients (4% vs 0%, P = 0.007). Three independent risk factors for DEP were identified: difficult interspinous space palpation (odds ratio [OR], 6.1; 95% CI, 2.8-13.9), spinal deformity (OR, 2.4; 95% CI, 1.1-5.3), and inability to flex the back (OR, 3.0; 95% CI, 1.2-7.8). The C-index of the model was 0.81 (95% CI, 0.74-0.88) in the training set and 0.78 (95% CI, 0.70-0.86) in the validation set. A 5-point score was created to define groups with low risk (score 0), intermediate risk (score 1-2), and high risk (score 3-4), with predicted rates of DEP of 9.7%, 30.3%, and 68.9%, respectively. The C-index of the score was 0.79 (95% CI, 0.72-0.86) in the training set and 0.76 (95% CI, 0.69-0.84) in the validation set. Decision curves support the clinical usefulness of the score. CONCLUSIONS: This study confirms risk factors for DEP and proposes a score to predict DEP. The score identifies high-risk patients who may benefit from an intervention to decrease DEP. This hypothesis should be evaluated in an impact study

Assessment of salivary amylase as a stress biomarker in pregnant patients.: Salivary alpha-amylase: a stress biomarker in pregnant patients

International audienceBACKGROUND: Chronic stress during pregnancy has been associated with worsened maternal and fetal outcomes. Acute stress immediately before spinal anaesthesia for caesarean section may contribute to hypotension. Therefore objective measures of acute stress may help identify women at risk of adverse outcomes. Salivary alpha-amylase is a stress biomarker that has so far been poorly investigated during pregnancy. The reference change value is the difference between two sequential results that must be exceeded for a change to be considered clinically relevant. Our first aim was to determine if salivary alpha-amylase increased in pregnant patients when subjected to the stress of transfer to the operating room. Our second aim was to determine if changes in salivary alpha-amylase were likely to be clinically significant by measuring reference change value in healthy volunteers. METHODS: In 15 pregnant patients undergoing planned caesarean section under spinal anaesthesia, salivary alpha-amylase, systolic blood pressure, heart rate, and immediate anxiety were measured on the morning of surgery on the ward and again in the operating room. The reference change value was calculated from 18 healthy volunteers. RESULTS: A median 220% increase in salivary alpha-amylase activity (P=0.0015) and a 17% increase in systolic blood pressure (P=0.0006) were observed between the ward and operating room. No changes of immediate anxiety or heart rate were observed. Reference change value was ±76% in volunteers and 13 of the 15 pregnant patients had a salivary alpha-amylase increase greater than the reference change value. CONCLUSION: When pregnant women are taken to the operating room, a clinically and statistically significant increase in salivary alpha-amylase was observed. Further studies are required to define its clinical usefulness